OPEN CALL: Remote Desktop - Blank Wallpaper change

Novell Cool Solutions: Feature

Tony K. just submitted this request for an Open Call, and we thought it was well worth looking into. If you have any suggestions or ideas for Tony, let us know.

When you are remote controlling a machine, it would be cool to have the blank screen a different colour from Black, or a splash screen instead. This is what I'm asking -- I'm sure it is some magic Workstation Policy
and some clever scripting, but I have yet to find anything on the
Internet that gives any clues, however it might be a further feature to
be considered for the ZENworksworks suite.

Here's how the request has come about.

A colleague asked an interesting request today. He is involved in
upgrades in some libraries, usually he locks the keyboard and blanks the
screen to prevent interaction from users. However this seems to fall
foul of some people being unable to gain access, or being unaware of the
upgrade in progress, so that they turn the PC off.

To have the PC turned off on you is a bit of a bind. However is there
any way of replacing the black blank screen, with a
pre-configured splash screen saying something useful like "This PC is
currently being upgraded, please contact the IT helpdesk should you have
any enquiries etc., etc.".

A simple solution is to have a splash screen if installing with an ACU,
then lock the keyboard and mouse. However it does depend on the type of
work you are doing, if you are doing manual configuration, etc.

I have noticed in RMErrorLog file that there is a call -
"CMD_SUPRESS_WALLPAPER"

What is making these calls? Can these be configured? Where does the
black background come from, is it a value, i.e. 1=black, 2=white,
3=green etc. Could you create a pointer to a file?

Would it be possible to have something that allows you to call a
pre-configured image? Of course you would have to be careful how this is
done. The last thing you want is some clever user substituting the file with
something "inappropriate" - now that would be annoying - so perhaps this
file should reside on the Server side, rather than the desktop.

If anyone out there has any ideas on this, I think it may prove to be a
very useful Cool Solution to some techies out there, but would be
challenging all the same.

Tony's follow-up:

Had a thought about this, and thinking about it now, it is obvious and
don't get why I didn't twig earlier.

When you blank the screen it locks the keyboard and mouse. What it is
really doing is putting the screen into power-save mode. There is no
wallpaper.

In power-save mode the PC looks switched off.

If I disable power save on the PC, ZENworks overides it and puts it into
power save mode. If we could overide the power saving option, then in
affect you'd be remoting a PC with a locked keyboard and no screen blank
at all.

As an experiment I backed up then deleted from the registry:
HKEY_CURRENT_USER\Control Panel\PowerCfg

By doing this there is no way the PC would know what power-save mode to
use. Interestingly, however, ZENworks can still blank the screen, however
moving the mouse takes it out of power save but it is put into power
save mode virtually immediately.

So in hindsight, I don't think this is possible. The only thing I can
think of is a third-party tool, but even then how do you get it in front
of the desktop you are working on to obscure the view, but maintain
privacy?

But a darn good idea for whoever can pull it off.

Tony's second follow-up:

Follow up to this, and something interesting.

When a workstation's display settings are out of range, the monitor or display will shut down to protect it, but you can remote the workstation to remedy the problem.

The key problem is a blank screen will prompt someone at a remote site to turn the workstation off thinking it is off already. This is the problem.

However the output of the screen isn't the same as you, the remote controller, see.

Here is a theory I mused and tested.

Hotkeys - pesky things that makes it rather interesting for end users when inadvertently activated. It also makes for a nice prank to play on co-workers (not that I do that sort of thing of course).

However on a target PC I activated Hotkeys and turned the display upside down. I remote-controlled the PC and - hey presto - the screen appears correct for me, but at the other end it is rather disorienting, and with keyboard and screen-lock on, you are not going to be disturbed. People could still see what you are working on, but you could perhaps have a desktop wallpaper upside down so it reads the correct way up "This workstation is in use, if you require assistance, please contact a member of staff". With the display in such a peculiar state, it would be very difficult to follow what is happening.

It does look rather confusing to remote a PC with the wallpaper the wrong way around and the icons correct. All you need to do is to remember to put the display back after you finish!

Hopefully this will stop members of the public turning the PC off.

Tony's third follow-up:

Yet another follow-up.

I showed my colleague what I found with regards flipping the screen, and he wasn't impressed (typical). "We disable screen rotation by default in libraries as it freaks people out".

Hmm..... okay.

However, another thought crossed my mind.

We use Remote Desktop Connection (RDC) on some Windows Servers and I commented on the fact that if I remote onto a server, someone else can too, and the desktop they see isn't what I see.

"Of course not, your PC is displaying the desktop itself".

Okay. I had remote-controlled the PC, my colleague connected via RDC and - hey presto - the screen locked itself on the target PC, but I could see my colleague's RDC session.

In a nutshell, all you need to do is connect via ZENworks, login, screen-lock the workstation (perhaps a funky alternative unlock message displayed - not sure how to change that just yet - just give me time), then RDC. You can see the screen, the user can't.

A bit long winded - but works. Just got to be careful you don't get stuck in a loop, as on the target screen, when it got to the login screen again, all I could see was the RDC session - not very helpful if the workstation is 2 miles away! However practice makes perfect, so you'll soon get the hang of it.

My assumption is this only applies to OS XP and above.

Hope this is more help.

Tony's fourth and fifth follow-ups: New

Hello - another follow up.

I conducted further testing, and my colleague David Walpole pointed out that you can simply use an RDC session and not bother with ZENworks.

However depending on the situation you could use ZENworks to login then lock the PC, then RDC.

Logged in as RDC, it will screen lock, and it does say "Remote Desktop is in use and has locked this computer". So you would need to log in as Admin to get into it. If this was in an area such as a library, the end user wouldn't have this.

My only concern is you could have a PC screen locked and the user away, you could use RDC to get on the PC, the screen then locks with the RDC screen lock and you can use ZENworks or RDC to browse on the screen and the user would not even realise.

My colleague said "just use RDC", however my concern is the differences between the desktops, as wallpaper I set was still in the RDC session, but not on the actual desktop. This raises the concern of the changes you make via RDC - do they apply to the PC, so I would use ZENworks to remote the PC, but this hooks on behind the RDC screen.

You would need to use RDC to log out, otherwise you have a locked workstation the end user can't use, the only other way would be to reboot the workstation via one of the sessions.

Of course for security reasons you might not want Terminal services running.

In hindsight (add-on to the last e-mail), you would have to get control again via ZENworks, if you log off via RDC, the Ctrl-Alt_Del screen is there, but ZENworks is confused as when you try and remote the workstation you get a blank screen - which isn't terribly useful, but once someone logs in, hey presto.

Further digging on RDC and using ZENworks in a more clandestine manner might be something some might want to look into.